Cassava

Cassava is grown predominantly by smallholder farmers across the tropics, prized for its flexibility: roots can often be left in the ground beyond physiological maturity and harvested as needed, functioning as a form of on-farm food storage.

Its tolerance of poor soils, erratic rainfall, and low-input management makes it an important food-security crop, though yields respond substantially to improved varieties and better agronomic practice where these are available.

Family

Euphorbiaceae (spurge family)

Genus

Manihot

Principal species

Manihot esculenta (cultivated cassava)

Growth habit

Woody perennial shrub propagated from stem cuttings, grown for enlarged starchy storage roots

Cassava originates from South America, where it was domesticated by indigenous peoples, and was subsequently introduced to Africa and Asia by traders, becoming deeply embedded in food systems across the tropics.

It is now grown across tropical Africa, Asia, and Latin America, with Africa accounting for a large share of global production. Current production and trade figures are compiled by FAO and national statistical services.

Cassava is well adapted to warm, humid to subhumid tropical climates and tolerates extended dry periods better than most staple crops, shedding leaves under drought stress and resuming growth once moisture returns.

The crop is frost-sensitive and cold intolerant, restricting production to frost-free tropical and warm subtropical zones.

Cassava tolerates a wide range of soils, including sandy and lateritic soils of relatively low fertility, and is often grown on marginal land where other crops perform poorly. Well-drained soils are preferred, since waterlogging can cause root rot.

Cassava is established by planting mature stem cuttings, selected from disease-free plants, either horizontally, at an angle, or vertically depending on local practice and soil moisture conditions.

• Selection of clean, disease-free planting material from healthy stems
• Land preparation appropriate to soil type, often involving mounding or ridging in heavier or wetter soils
• Weed control during early establishment, when the crop canopy has not yet closed
• Intercropping with legumes or vegetables during the early growth phase in many smallholder systems

Potassium is removed in large amounts by cassava roots and strongly influences root bulking and starch content, while nitrogen supports canopy development. Cassava can produce a harvest on low-fertility soils, but yields respond to improved nutrient management.

Cassava is grown predominantly under rain-fed conditions given its drought tolerance, though supplemental irrigation can improve establishment and yield in areas with pronounced dry seasons or on very sandy soils.

Water stress during root bulking has less impact on cassava than on many other staple crops, a key reason for its role in drought-prone farming systems.

Cassava bacterial blight causes wilting and dieback and can spread rapidly under wet, windy conditions, while anthracnose affects stems and can weaken planting material for the following season. Mealybugs and whiteflies are significant sap-feeding pests; whiteflies are also vectors of important cassava viruses.

Management relies on clean planting material, resistant or tolerant varieties where available, field sanitation, and — where justified — locally authorized control products applied according to their labels.

Roots are typically harvested by hand, lifted from the soil, from around eight months to two years after planting depending on cultivar and intended use. Because roots deteriorate rapidly once lifted, harvest is often timed close to processing or sale.

• Staple food starch, consumed fresh, dried, or processed (e.g. as flour or granules)
• Industrial starch for food and non-food manufacturing
• Animal feed from roots, leaves, and processing by-products
• Planting stems retained as propagation material for the next crop cycle